Optical transceiver with a pluggable function

ABSTRACT

The optical transceiver of the present invention is one type of the pluggable transceiver that is inserted into/extracted from the cage in the host system. The transceiver includes the OSA (Optical Sub-Assembly) unit, which shows the optical function, and the body unit installing the electronic circuit. The OSA unit includes the receptacle member, the tab plate and transmitting/receiving sub-assemblies. The body unit includes the base installing the circuit board, the heat conducting plate to conduct heat generated by the IC on the substrate to the rear end of the transceiver, the supplementary substrate, the supporting plate, and the cover for putting these components therein. In the present transceiver, the heat is effectively conducted to the rear end thereof the heat conducting plate, besides, the tab plate, the heat conducting plate, and the supporting plate are made only by cutting, bending and tapping without any welding and gluing. Therefore, the present invention may provide an optical pluggable transceiver with superior heat dissipating function by cost saved configuration.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuous-in-part of U.S. patentapplication Ser. No. 11/242,148, filed Oct. 4, 2005, which claims thebenefits of U.S. provisional patent applications Ser. No. 60/615,587,filed Oct. 5, 2004, Ser. No. 60/620,325, filed Oct. 21, 2004, Ser. No.60/632,937, filed Dec. 6, 2004, and Ser. No. 60/652,846, filed Feb. 15,2005, which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a structure of a pluggable opticaltransceiver, and a method for manufacturing the same.

2. Related Prior Art

The pluggable transceiver 1 (hereinafter denotes as transceiver) shownin FIG. 1A is used by being inserted into the cage 2 provided on thecircuit board of the host system. The transceiver 1 inserted into thecage 2 is shown in FIG. 1B. On the bottom of the cage 2 is formed withstud pins 2 c, and the cage 2 is installed on the circuit board of thehost system by soldering these stud pins 2 c to the circuit board so asto expose the opened end 2 a from the face panel of the host system. Inthe inner end of the cage 2 is provided with an electrical connector 2 bsuch that the each electrode of the connector 2 b is in contact to, orsoldered to the wiring pattern on the circuit board. By inserting thetransceiver 1 into this cage 2, the electrical plug configured in therear end of the transceiver 1, mates with this connector 2 b within thecage to enable the transceiver 1 to communicate with the host system. InFIG. 1B, the host system, the circuit board and the face panel thereof,are omitted. Moreover, to configure the electrode of the plug makes thetransceiver 1 so-called hot-pluggable, by which the transceiver 1 isable to insert into/remove from the cage 2 as the host system is poweredon.

The cage 2, as shown in FIG. 1B, is a metal box with one end 2 a beingopened. Although a tip of the tab plate protrudes from the cover 23 ofthe transceiver 1, when the transceiver 1 is set within the cage 2, thistab plate 14 is also set within the cage 2 as the tip thereof coming incontact to the inside of the cage 2. Moreover, a plurality of fins 2 dextends outward in the front portion thereof to surround the opened end2 a. When the cage 2 is installed on the circuit board of the hostsystem, these fins 2 a come in electrically contact to the face panel toshield the transceiver 1 and the host system.

Some multi-source agreements (MSA) rule the outer dimension and theelectrical specification for such pluggable transceiver. The normaloperation can be ensured as long as the transceiver follows theagreements, even when such transceiver is provided from theextraordinary manufacturer. Further, since the agreement rules the outerdimension, the insertion/extraction of the transceiver is also ensured.

However, the cage itself is made of a thin metal plate to deform in easeby an extra force, even by the insertion/extraction of the transceiverto the cage. The tab plate is necessary to come in reliable in contactto such deformed cage. The tab plate is provided to secure the EMI(Electro-Magnetic Interference) shield function for the transceiver 1.Recently, the operational speed, i.e., the clock speed of thetransceiver reaches and exceeds 1 GHz. In such high speed operation, thehigh frequency signal is firmly prevented from leaking from theequipment. The tab plate is necessary to come in contact to thephysically deformed cage 2.

Another subject under such high operational speed is that, the activedevices, such as ICs and transistors, installed within the transceiverbecomes necessary to be provided with large current to operate in a highfrequency band, which results in the further heat being generated in thedevices and the request to provide a further effective mechanism for theheat dissipation. However, the transceiver is unable to touch the casethereof in tight to the cage because the pluggable transceiver isinherently assumed to be inserted into/extracted from the cage 2.Tightly and firmly touching to the cage disturbs the smoothinsertion/extraction of the transceiver.

Further, the transceiver comprises of three parts, namely, subassembliesto covert an optical signal to an electrical signal, or an electricalsignal to an optical signal, a body portion installing the electroniccircuit and an optical receptacle, and an mechanism to engage thetransceiver with the cage. The U.S. Pat. No. 6,349,918 has disclosed theengaging mechanism using a bail and an actuator. Rotating the bail infront of the optical receptacle, one end of the bail pushes up theactuator, accordingly, the other end of the actuator is pressed down todisengage with the cage because the actuator moves in the seesaw motion.The other United States patent application published as US-2003/0142917Ahas also disclosed a similar mechanism.

Recently, one application has been proposed that, a plurality oftransceivers is densely arranged to configure an optical hub system forthe optical communication. For example, to arrange the transceiver, thecross section of which is about 1 centimeter square, by 16 pieces inhorizontal and two to four in vertical forms the hub system providing 32to 64 optical channels. In such system, when the target transceiver isto be removed from the cage as the other cages surrounding the targettransceiver are set with transceivers each providing an optical cable,the bail of the target transceiver is hard to rotate because theneighbor transceivers and their optical cables prevent from touchingthereto, which prohibit the target transceiver from being extracted fromthe cage.

Therefore, the present invention is to provide a new structure of theoptical pluggable transceiver based on the MSA and a method formanufacturing the same. The transceiver according to the presentinvention, not only satisfies the MSA standard, but also ensures thereliable shielding by effectively covering the body of the transceiverand stably touching body to the cage, provides the effective heatdissipation mechanism from the devices to the outside thereof, andprovides a disengaging mechanism with the cage even a plurality oftransceivers with the optical cable is densely arranged.

SUMMARY OF THE INVENTION

One aspect of the present invention relates to a structure of apluggable optical transceiver that is inserted into or extracted fromthe cage of the host system. The cage exposes one end portion thereoffrom the face panel of the host system to receive the pluggabletransceiver, and provides an electrical connector in the other end. Theconnector is mounted on the circuit board of the host system.

The optical transceiver of the present invention comprises an opticalassembly unit and a body unit. The former unit includes a receptaclemember, a tab plate and an optical sub assembly. On the other hand, thelatter unit includes a substrate, a base, a heat conducting plate, and acover. The receptacle member may be made of resin and configured with anoptical receptacle for receiving an optical connector with an opticalfiber. The tab plate is made of metal and engaged with the receptaclemember. The optical subassembly, which may include a transmittingoptical subassembly (TOSA) and a receiving optical subassembly (ROSA)when the transceiver performs a full duplex communication, includes asemiconductor optical device that is optically coupled with the opticalfiber within the optical connector. This optical subassembly isinstalled on the receptacle member.

The substrate mounts an electronic circuit and mates with the electronicconnector within the cage. The base, which is made of metal, installsthe substrate and is engaged with the optical assembly unit. The heatconducting plate, which is also made of metal, is in contact to theelectronic circuit mounted on the substrate. This heat conducting plateis engaged with the base. The cover, which is also made of metal, putsthe base, the heat conducting plate, the optical subassembly and thesubstrate therein.

One feature of the transceiver according to the present invention isthat these metal tab plate, the metal base, the metal heat conductingplate, and the metal cover are, although the materials may be differentform each other, all made from a metal plate by cutting, bending, andtapping without welding and gluing. Due to this configuration, not onlythe material cost of the transceiver may be reduced but also themanufacturing process thereof may be simplified, thereby reducing thecost thereof.

The receptacle member of the invention may include first to thirdportions. The first portion is configured to form the opticalreceptacle. The second portion forms a first projection in an outer sidethereof. The third portion forms a second projection in an outer sidethereof. The tab plate may include first and second portions. The firstportion of the tab plate forms a latch tab engaged with the firstprojection of the receptacle member. The second portion is folded twiceto form a U-shaped cross section, and the third portion of thereceptacle member is put between this U-shape portion.

Thus, the tab plate may be assembled with the receptacle member only byinserting the third portion of the receptacle member into the secondportion of the tab plate and by engaging the latch tab of the tab platewith the first projection of the receptacle member. Therefore, themanufacturing cost of the transceiver may be reduced. The tab plate mayalso provide a socket to receive the center post of the base.

The base may include a bottom, a pair of sides extending from the base,and a center post also extending from an end of the bottom. Thereceptacle member may include a pair of sides forming a secondprojection and a center partition for forming a cavity to install theoptical subassembly therein. The receptacle member may further include aplateau behind the center partition. This plateau abuts against thecenter post of the base.

The side of the base may include a support with an opening. This openingengages with the second projection of the receptacle member. Thus, thebase and the receptacle member of the present invention may be assembledto each other by inserting the center post of the base into the socketof the tab plate, abutting the tip thereof against the plateau of thereceptacle member and engaging the second projection of the receptaclemember with the opening of the base, without any screwing. Therefore,the manufacturing cost of the transceiver may be reduced. Moreover, theengagement of the base with the receptacle member and the tab plate maybe carried out in compensate, that is, the former engagement of thecenter post to the socket is carried out between the convex in the baseand the concave in the receptacle member, while, the latter engagementbetween the projection in the receptacle member and the opening in thebase is carried out between the concave in the base and the convex inthe receptacle member, which may strengthen the engagement.

The base of the present invent may include a first portion for mountingthe substrate and a second portion for engaging with the heat conductingplate. The second portion may include a pair of coupling surface with aslit therebetween. Each coupling surface has firs and second fittingsurfaces bent downward along a longitudinal direction of thetransceiver. On the other hand, the heat conducting plate may includefirst to fourth portions. The first portion is in contact to theelectronic circuit on the substrate. The second portion is in contact tothe coupling surfaces of the base. The third and fourth portions of theheat conducting plate each includes a surface fitted to the first andsecond fitting surface of the coupling portion.

The heat conducting plate may further include, in the second portionthereof, a pair of fitting tabs and a spacer tab both bent downward. Thespacer tab has a width slightly larger than that of the slit between thecoupling portions of the base. On the other hand, the base may furtherinclude, in the coupling surface thereof, a pair of tabs each bentdownward. These tabs are in contact to the fitting tab of the heatconducting plate. Thus, the coupling surface of the base is put betweenthe spacer tab and the fitting tab of the heat conducting plate. Thatis, the spacer tab presses the coupling surface of the base outward,while, the fitting tabs abut against the tab of the coupling surface topress inward. Thus, the base and the heat conducting plate of thepresent invention is assembled only by fitting to each other without noscrewing, which may simplify the manufacturing process and reduce thecost thereof.

The optical transceiver of the present invention may further include asupplementary substrate to mount a supplementary circuit. Thesupplementary substrate, electrically connected to the primary substratewith a flexible printed circuit board, is mounted on the heat conductingplate so as to fold the flexible printed circuit board. The flexibleprinted circuit board provides a projection that is set behind thecoupling portion of the base. Since this configuration hides the edge ofthe flexible printed circuit board by the base, the cover does not hookthe board when the cover is set to the body unit.

The optical transceiver may further include a supporting plate toposition the supplementary substrate. That is, the heat conducting platemay further include, in the first portion thereof, a supporting postbent upward. On the other hand, the supporting plate may include firstto fourth portions. The first portion is inserted under the heatconducting plate and has a pair of legs each having a step inserted intothe notch of the supplementary substrate. The second portion includes asurface abutted against the side of the supporting post. The fourthportion has a pair of legs each having a step engaged with the stepformed in the end of the supplementary substrate. The third portion thatconnects the second portion with the fourth portion is configured withan arched shape protruding outward. When the cover is set to body unit,the cover presses the third portion of the supporting plate,accordingly, the supporting plate presses down the supplementarysubstrate. Thus, the supporting plate of the present invention may beassembled with the supplementary substrate and the heat conducting plateonly by fitting without any screwing, which may also reduce themanufacturing cost.

The optical transceiver of the invention may further include a bail andan actuator for providing the releasing mechanism of the transceiverfrom the cage. The optical receptacle member may further providestructures to assemble these bail and actuator. That is, the receptaclemember may provide third projections in both outer sides thereof, and acenter projection and a pair of beaked hooks in the bottom surfacethereof. The bail is configured with a pair of legs each having anopening for receiving the third projection and a bridge portionconnecting these legs. The actuator has a hollow for receiving thecenter projection, an axis that is fitted into the beaked hook, and anengaged projection in a tip thereof. To rotate the bail with the thirdprojection as a center of the rotation causes a seesaw motion of theactuator around the axis thereof, which draws the engaged projectioninward to release the optical transceiver from the case. Thus, thepresent transceiver assembles with the bail and the actuator only byfitting, which reduces the manufacturing cost.

Moreover, the actuator of the present transceiver includes a pressingsurface in the end opposite to the side where the engaged projection isformed in the tip thereof. To press the pressing surface of the actuatorcauses a rotational moment to the bail, which enables to release theoptical transceiver from the cage.

Still further, the bridge portion of the bail may provide a color codeto identify an emission wavelength of the transceiver. When thetransceiver is applied to the wavelength division multiplex (WDM)system, the emission wavelength is necessary to identify in precise.However, when the transceiver is set within the cage, the information ofthe emission wavelength is unable to distinguish even such informationis recorded in the label stuck in the top and side surfaces of thetransceiver. In the configuration that the emission wavelength isidentified by the color code marked in the bridge portion of the bail,the information may be easily distinguished.

The base of the present invention, in the bottom thereof, may include arib extending along a longitudinal direction and hollowed inward. On theother hand, the cover inevitably includes a slit extending along thelongitudinal direction because the cover is made from a metal plate. Inthe present invention, a pair of edges forming the slit is each setwithin the rib. Therefore, the strength of the base and the cover may beenhanced by the rib and the edge within the rib, respectively.

The base according to the present invention may have a finger in thefront end thereof to hold and to push the optical subassembly. The tipshape of the front finger of the base may trace the outer shape of theoptical subassembly. The front finger may be divided into a plurality offingers each bent from the primary surface of the base to form a gap. Ashield block may be inserted into the gap. Moreover, an envelop curve ofthe tip of the bent fingers may trace the outer shape of the opticalsubassembly.

The optical transceiver may further include a shield plate, which isalso made of metal, assembled with the optical subassembly. The shieldplate comes in electrically contact with the base and the tab plate toshield the optical transceiver effectively.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A illustrates the outside appearance of the pluggable transceiverof the present invention, and FIG. 1B illustrates the transceiver setwithin in the cage;

FIG. 2 is an exploded view of the transceiver according to an embodimentof the present invention;

FIG. 3A illustrates the receptacle member and the tab plate to beattached with the receptacle member, and FIG. 3B illustrates thereceptacle member assembled with the tab plate;

FIG. 4A illustrates a process for assembling the optical subassemblieswith the receptacle member, and FIG. 4B illustrates the opticalsubassembly installed on the assembly of the receptacle member with thetab plate to form the OSA unit;

FIG. 5A shows the configuration of the base, and FIG. 5B illustrates theprimary substrate, the supplementary substrate, and the insulating filminserted between the heat conducting plate and the supplementarysubstrates when the supplementary substrate is assembled on the heatconducting plate;

FIG. 6A is a downward view of the primary substrate temporarilyassembled with the OSA unit and the base, and FIG. 6B shows a processfor assembling the base with the primary substrate and the OSA unit;

FIG. 7A illustrates a process for assembling the heat conducting platewith the base and the primary substrate, and FIG. 7B illustrates theheat conducting plate partially assembled with the base;

FIG. 8A illustrates the OSA unit, the base, the primary substrate, andthe heat conducting plate assembled with each other, and FIG. 8Billustrates the assembly where the supplementary substrate is set on theheat conducting plate;

FIG. 9A is a downward view of the heat conducting plate, while FIG. 9Bis an upward view thereof;

FIG. 10A illustrated a modified heat conducting plate to be assembledwith the modified base, and FIG. 10B illustrates the assembly of themodified heat conducting plate together with the modified base;

FIG. 11A illustrates the process for assembling the supporting platewith the heat conducting plate, FIG. 11B illustrates the body unit withthe supporting plate assembled with the heat conducting plate, and FIG.11C illustrates the supporting plate;

FIG. 12A illustrates the transceiver assembled with the actuator, FIGS.12B and 12C are upward and downward views of the actuator, respectively,and FIG. 12D illustrates a portion of the receptacle member to beengaged with the actuator;

FIG. 13A illustrates the assembly of the receptacle member, theactuator, and the bail, and FIG. 13B shows the bail slightly rotatedfrom the initial position;

FIG. 14A illustrates the body unit and the cover to be set thereto, andFIG. 14B is a cross section of the cover taken along the line A-A inFIG. 14A;

FIG. 15A illustrates the ground fin provided in the tip of the tab plateand that of the upper front of the cover, and FIG. 15B illustrates thebottom front of the cover;

FIG. 16 is plan views of the transmitter optical subassembly (TOSA) andthe receiver optical subassembly (ROSA), each installed within theoptical transceiver according to the present invention;

FIG. 17A shows a front end portion of the base according to embodimentsof the present invention, and FIG. 17B is a front view of the base,where two OSAs are virtually shown by their outer diameter;

FIG. 18A shows a process for assembling a shield block between frontfingers of the base, and FIG. 18B shows the shield block set between thefront fingers of the base;

FIGS. 19A and 19B shows shield plate according to an embodiment of thepresent invention; and

FIG. 20A is a perspective view showing a process for setting the shieldplate within the second necked portion of the OSA, and FIG. 20B is aplan view showing the shield plate, the necked portion of the OSA, andthe receptacle member assembled with the tab plate, the OSA, and theshield plate.

DESCRIPTION OF PREFERRED EMBODIMENTS

Next, a configuration of an optical transceiver and a method forassembling the transceiver according to the present invention will bedescribed as referring to accompanying drawings. FIG. 2 is an explodedview of the optical transceiver of the present invention. The pluggabletransceiver 1 shown in FIG. 2 comprises a body unit and an opticalsubassembly unit. The body unit includes a primary substrate 17, asupplementary substrate 18, a supporting mechanism of these substrates,and a cover 23. The supporting mechanism comprises a base 20, aheat-conducting plate 21 and a supporting plate 22. The opticalsub-assembly (OSA) unit includes transmitting and receiving opticalsubassemblies, 15 and 16, respectively, and members, 11 to 14, to showthe optical coupling function as described below.

(OSA Unit)

The OSA unit includes, in addition to two optical subassemblies, 15 and16, a receptacle member 13 made of resin, an actuator 12, a bail 11 anda tab plate 14. The bail 11 may be made of resin or metal. The bail 11and the actuator 12 perform a mechanism to disengage the transceiver 1from the cage 2. As described later in this specification, to rotate thebail 11, with a projection formed in both sides of the receptacle member13 as the center of the rotation, moves the front end of the actuator 12downward. The actuator 12 is fixed to the receptacle member 13 in thecenter thereof. Accordingly, due to the seesaw motion as this fixedpoint being the center of the rotation, the rear end of the actuator 12is lifted upward, which pulls the projection formed in the tip of therear end of the actuator 12 inward to release the engagement of theprojection with the opening of the cage 2.

As for the releasing mechanism by the combination of the bail 11 and theactuator 12, it is known that the actuator 12 is slid backward as therotation of the bail 11. In such mechanism, the projection to be engagedwith the cage is fixedly formed in the bottom of the receptacle member13 not the tip of the actuator 12. Inserting the transceiver 1 into thecage 2, the projection in the bottom of the transceiver engages with theopening of the cage 2 as deforming the cage 2. When releasing thetransceiver 1 from the cage 2, the rear end of the actuator 12 spreadsthe cage 2 outward as sliding the actuator forward, thus disengaging theprojection from the opening of the cage 2.

In both mechanisms, the rotation of the bail 11 releases the engagementof the transceiver 1 with the cage 2. In other words, it is notrestricted to those mechanisms mentioned above as long as thetransceiver provides a mechanism to release from the cage 2 and therotation of the bail 11 originally causes this mechanism.

FIG. 16 shows an example of the TOSA 15 and the ROSA 16. Bothsubassemblies provide a CAN package that includes a stem, 15 a or 16 a,a plural lead pins, 15 b or 16 b, protruding from the stem, a cap, 15 gor 16 g, and a sleeve, 15 d or 16 d. A semiconductor optical device isinstalled within a space formed by the stem, 15 a or 15 b, co-operatingwith the cap, 15 g or 16 g, respectively. Between the sleeve, 15 d or 16d, and the cap, 15 g or 16 g, is provided with a plurality of flanges,15 c or 16 c, and between the flanges are formed with two neckedportions, 15 e or 16 e, and 15 f or 16 f, respectively. As explainedlater, by setting the necked portion, 15 e or 16 e, to the receptaclemember 13, the OSA may be positioned in the receptacle member. Moreover,the other necked portion, 15 f or 16 f, receives the shield plate 40.

An assembly of the receptacle member 13, the tab plate 14 andsubassemblies, the TOSA 15 (Transmitting Optical Sub-Assembly) and theROSA 16 (Receiving Optical Sub-Assembly), installed in the receptaclemember 13, is called as an OSA unit 6 as a whole. From FIG. 3A to FIG.4B show the process to assemble of the OSA unit 6. These figures arethose viewed from the bottom side of the transceiver.

The OSAs includes the TOSA 15 and the ROSA 16 when the transceiver 1 hasa function of the full-duplex communication standard. Both OSAs, 15 and16, has a coaxial package. The ROSA 16 installs a semiconductorlight-receiving device, which is typically an avalanche photodiode, APD,or a PIN-PD, collectively called as the PD, and a preamplifier foramplifying an electrical signal generated by the PD. On the other hand,the TOSA 15 installs a laser diode (LD) and, in addition to the LD, a PDfor monitoring the optical output from the LD. A thermo-electric device,called as a Peltier device, may be also installed within the TOSA 15.Moreover, when the driving frequency of the LD exceeds 10 GHz, thedriver for the LD may be also installed within the TOSA 15. The signalsand power lines from the OSA to the substrate 17, or from the substrate17 to the OSA, are transferred through lead pins, 15 b and 16 b,provided in the rear end of the OSA, which is so-called the stem, 15 aand 16 a. A flexible printed circuit (FPC) board may be used in place ofthe lead pins, 15 b and 16 b.

The receptacle member 13, which is made of resin, includes first tothird portions, 13 a to 13 c, as shown in FIG. 3A. The first portion 13a, positioned in the front end of the receptacle member 13, provides twocavity, 10 a and 10 b, into which the optical connector is to beinserted. These cavities are called as the optical receptacle. The outerside of the first portion 13 a forms a projection 13 d that becomes anaxis of the rotation of the bail 11. The bottom of the first portion 13a forms a projection 13 e in the center and two beaked hooks 13 f inboth sides of the projection 13 e. These structures are arranged alongthe boundary to the second portion 13 b, as shown in FIG. 3A that lookdowns the bottom of the receptacle member 13. The center projection 13 emates with the hollow formed in the center of the actuator 12 and twobeaked hooks receives the axis 12 g, which enables the actuator 12 tooperate in the seesaw motion around the axis 12 g.

The second portion 13 b includes side walls and a center partition 13 i,which forms two cavities 13 k to receive the TOSA 15 and the ROSA 16,respectively. The bottom of the cavity 13 k is opened in order to setthe OSA therein. U-shaped cuttings are formed in the boundary wall 13 qto the third portion 13 c. The U-shaped cutting provides a groove 13 jalong the exposed section, which receives one of the flange, 15 c or 16c, of the OSA to position the OSA in the cavity 13 k. Thus, setting theOSA within in the cavity 13 k, the sleeve, 15 d or 16 d, formed in thehead portion of the OSA, protrudes into the optical receptacles, 10 aand 10 b, of the first portion 13 a. Accordingly, the semiconductoroptical device such as LD or PD installed within the OSA may opticallycouple with the optical fiber in the optical receptacles, 10 a and 10 b.The optical fiber provides, in the tip thereof, the optical connector tobe inserted into the receptacle. Since the physical dimensions of theoptical receptacles, 10 a and 10 b, and the position of the sleeves, 15d and 16 d, with respect to the optical receptacles, 10 a and 10 b, areprecisely ruled, the position of the OSA, 15 and 16, in particular thesleeve thereof, must be positioned with respect to the receptacle member13.

In a center of the side wall 13 h forms a projection 13 g. As describedlater in this specification, to mate this projection 13 g with anopening in the tab plate 14 and an opening in the cover 23 assembles thetab plate 14 and the cover 23 with the receptacle member 13. Theprojection 13 g has a gentle slope in a side where the tab plate 14 isinserted to mate the projection 13 g smoothly with the tab plate 14,while, another side thereof has a steep slope in order to prevent thetab plate 14 and the cover 23 once engaged with the projection 13 g fromeasily releasing.

The third portion 13 c includes an upper wall 131 continued from theupper wall in the second portion 13 b and two projections formed in bothends thereof to mate with the base 20.

The tab plate 14 includes first and second portions, 14 a and 14 b. Thefirst portion 14 a forms a plurality of fins, 14 c, 14 d and 14 f, whichsurround the receptacle member 13 and extend outward. These fins, 14 c,14 d and 14 f, as described later, are to come in contact to the insideof the cage 2 to function the electromagnetic interference (EMI) shield.The fin 14 d in both sides and another fin 14 f in the bottom have ashape that the center portion 14 thereof protrudes to come in contactreliably to the inside of the cage 2. The tip of the fins, 14 c, 14 dand 14 f, configures in wavy and the bottom portion of this wave fitswithin the groove formed between the first 13 a and second 13 b portionsof the receptacle member 13. The fin 14 d in both sides has an opening14 e within which a latch tab 14 e is formed. A center hole of thislatch tab 14 e engages with the projection 13 g of the receptacle member13 to assemble the tab plate 14 with the member 13.

The second portion 14 b of the tab plate 14 is folded twice. That is, tobend a surface 14 g extending form the fin 14 f in almost right angleforms a surface 14 h, and to bend again in almost a right angle formsanother surface 14 i. The surfaces, 14 g and 14 i, put the upper wall131 of the receptacle member 13 therebetween. Thus, the tab plate 14 issecurely assembled with the receptacle member 13.

The second portion 14 b, bent in almost right angle to a directionopposite to the fin 14 f, forms a surface 141. This surface 141 providestwo cuttings tracing the U-shaped cutting of the receptacle member 13.In the deep end of this cutting provides a latch tab 14 k that fits tothe groove 13 n formed in the bottom of the U-shaped cutting of thereceptacle member 13 to position the tab plate 14 with respect to thereceptacle member 13. A center of this surface 141, between two U-shapedcuttings, forms a spacer 14 j by bending the tab plate 14. The width ofthe U-shaped cutting of the surface 141 is set slightly smaller than thediameter of the OSA. Accordingly, the OSA once set within the cutting ofthe tab plate 14, is hard to disassemble. The tip of this spacer iscurved inward to form a socket 14 n, into which the center post 20 f ofthe base 20 is inserted to build the base with the receptacle member 13.Moreover, a portion in the receptacle member 13 facing this spacer 14 jforms a plateau 13 r, against which the tip of the center post 20 f ofthe base 20 is abutted. The tab plate 14 is made from a metal plate witha thickness of about 0.15 mm and may be made of stainless steel only bycutting, bending and tapping without welding, gluing, or screwing, whichmay not only reduce the cost but also decrease the manufacturing cost.

FIG. 3B shows the assembly of the receptacle member 13 with the tabplate 14, FIG. 4A shows a process for setting the OSA into this assemblyof the receptacle member 13 with the tab plate 14, and FIG. 4B showsthat the OSAs, 15 and 16, are set within the cavities 13 k of thereceptacle member 13 with the flanges, 15 c and 16 c, aligned within theU-shaped cutting. Setting the OSA, 15 and 16, within the receptaclemember 13 together with the tab plate 14, a respective pairs of theflanges, 15 c and 16 c, of the OSA put the wall 13 q behind the groove13 j forming the U-shaped cutting therebetween together with the surface141 of the tab plate 14. Using the metal sleeve, 15 d and 16 d, andproviding the latch tab 14 k in the deep end of the U-shaped cutting ofthe tab plate 14, the electrical conduction from the tab plate 14 to themetal sleeves, 15 d and 16 d, may be ensured. Since the tab plate 14 isconnected to the cage 2 by the fins thereof, 14 c, 14 d, and 14 f, thepresent transceiver 1 may firmly and securely ground the metal sleeves,15 d and 16 d.

(Body Unit)

Next, the body unit of the transceiver 1 will be described. The bodyunit includes the base 20, the cover 23, the primary substrate 17, asupplementary substrate 1, the heat-conduction plate 21, and thesupporting plate 22.

FIGS. 5A and 5B show the primary and supplementary substrates, 17 and18, and the base 20. On the primary substrate 17 is installed with anelectronic circuit including an integrated circuit (IC) 17 c. A laserdriver for driving the LD, a signal processor for extracting a clockcomponent and a data component from an amplified signal sent from theROSA 16, or, when the APD is used as a light-receiving circuit, a biascontroller for generating and adjusting the reverse bias voltageprovided to the APD, are known as the electronic circuit installed onthe substrates, 17 and 18. Moreover, when the thermo-electric controllersuch as the Peltier device is installed within the TOSA 15, the Peltierdriver is also installed within the substrates, 17 and 18. When the sizeof the circuit above mentioned becomes large, or an additional circuitsuch as a processor for controlling in inclusive those circuits and amemory are necessary to be installed within the transceiver 1, thesupplementary substrate 18 may install circuits not processing a highspeed signal, typically the controlling circuit for the APD and thePeltier driver.

The primary substrate 17 connects to the supplementary substrate 18 witha FPC board 18 d. This FPC board 18 d is soldered to the primarysubstrate 17 extending from the side of the supplementary substrate 18.As described later, the supplementary substrate 18 is overlaid on theprimary substrate 17 by folding this FPC board 18 d. The insulating film19 is inserted between the supplementary substrate 18 and the heatconducting plate 21 to prevent the back side of the supplementarysubstrate 18 from electrically shorting to the heat conducting plate 21.

On the rear end of the primary substrate 17 is provided with anelectrical plug 17 f. This plug 17 f may mate with the electricalconnector in the deep end of the cage 2, which enables the electricalcommunication of the electrical circuit installed within the transceiver1 with that of the host system. To configure the electrode of this plug17 f with the predetermined pattern may realize the hot-pluggablefunction where the transceiver 1 may insert into or remove from the cageas the host system is powered on.

The electrical connection between the circuit installed on the primarysubstrate 17 with the OSAs, 15 and 16, are performed by lead pins, 15 band 16 b. The primary substrate 17 provides electrodes, 17 a and 17 b,each electrically connected to the lead pins, 15 b and 16 b, of the OSA.The FPC board may serve as the lead pins. When the operational speed ofthe transceiver 1 enters the zone over 1 GHz, it is preferable toconnect the OSAs, 15 and 16, to the primary substrate 17 with a meansthat secures the impedance-matching condition. Even the FPC boardconnects the OSAs, 15 and 16, to the primary substrate 17; theinterconnection formed on the FPC board may be a micro-strip line or aco-planar line with the impedance-matched configuration. Moreover, whenthe electrical connection is carried out under an impedance-mismatchedcondition, it is preferable to make the coupling means as short aspossible to suppress the deterioration in the signal transferred from/tothe OSAs, 15 and 16 by the impedance mismatching.

The primary substrate 17 forms a plurality of notches 17 e in the sidethereof. As described later, to fit this notch 17 e to the projection 20k formed in the base 20 and to abut the step 17 d formed in the rearside of the substrate 17 against the side wall of the coupling portion20 h automatically determines the longitudinal position of the substrate17 within the transceiver 1.

The base 20 covers the bottom side of the OSA and mounts the primarysubstrate 17 thereon. The base 20 is also made from a metal plate, suchas iron or stainless steel, by cutting, bending and tapping withoutgluing, welding and screwing, which reduces the cost of the transceiver1. That is, the base 20 includes a first portion 20 a and a secondportion 20 b. The first portion 20 a provides a space opened upward toinstall the primary substrate 17 thereon. The second portion 20 b,formed in the rear of the first portion 20 a, provides a space openeddownward to install the heat-conducting plate 21.

The first portion 20 a includes a bottom 20 g, a pair of sides 20 cextending from the bottom 20 g, a support 20 d that constitutes aportion of the sides 20 c, and a front wall 20 ne extending from thebottom 20 g at the front edge. On the center of the bottom 20 g isformed with a rib 20 q extending along the longitudinal direction of thetransceiver 1 and depressed inward. The front end of the bottom 20 gforms a center post 20 f that is, as aforementioned, inserted into thesocket 14 n of the tab plate 14, and abutted in the tip thereof againstthe plateau 13 r to assemble the base 20 with the receptacle member 13and the tab plate 14. The rib 20 q not only positions the cover 23 whenthe base 20 is put into the cover 23 but also mechanically strengthensthe base 20.

The bottom 20 g further forms two openings 201, through which thesoldering between the lead pins, 15 b and 16 b, of the OSA to theprimary substrate 17 may be carried out. The substrate 17 is adouble-sided wiring substrate to enhance the flexibility of theinterconnection. Although FIG. 5B illustrates electrodes, 17 a and 17 b,only on the front surface of the substrate 17, electrodes similar tothat of the front side are formed in the back side, and the lead pins,15 b and 16 b, sandwiches the substrate 17 to connect the lead pins tothe electrodes in both sides thereof. Since to set the substrate 17 tothe base 20 hides the electrodes in the back side, the openings 201exposes the electrodes and the lead pins in the back side to enable thesoldering.

The side for the TOSA in the bottom 20 g places the thermal sheet 27thereon in advance to the assembly. The thermal sheet 27 comes incontact to the stem 15 a of the TOSA 15 to dissipate heat generatedwithin the TOSA 15 to the cover 23 via the base 20. Although the ROSA 16generates heat greater than that from the TOSA 15 because the ROSAinstalls the pre-amplifier in addition to the PD, such circuit generallyshows the dull temperature dependence compared to that of the LD. The LDshows the strong temperature dependence in its light-emittingcharacteristic. Therefore, the thermal sheet 27 is provided only for theTOSA 13. When the preamplifier installed within the ROSA 16 generateslarger heat, for example, in the operational speed greater than 10 GHz,it is preferable to provide the thermal sheet for the ROSA 16.

The side 20 c forms a projection 20 k in a center thereof and two steps20 m putting the projection 20 k therebetween. The projection 20 k, aspreviously described fits into the notch 17 e formed in the side of thesubstrate 17 to position the substrate 17. The step 20 m stabilizes thesubstrate 17 by overlaying the substrate 17 thereon. Without the step 20m, the substrate 17 comes in contact to the base 20 only by the sectionof the side 20 c, which may be unstable for the substrate 17. The step20 m, which is formed by bending a portion of the side 20 c inward,secures the stability of the substrate 17 with respect to the base 20.

The front portion of the side 20 c forms the support 20 d continuouslyextending upward. The support 20 d provides the opening 20 e in a centerthereof that engages with the projection 13 m of the receptacle member13 to assemble the base 20 with the receptacle member 13. The front wall20 n configures a gentle U-shape that follows the outer shape of theOSAs, 15 and 16.

FIGS. 17A and 17B show a detail of the front end of the base 20. Oneembodiment of the front wall 20 n is shown right hand side of FIG. 17B,where the shape of the front wall 20 n traces the outer peripheral ofthe necked portion, 15 e or 16 e, of the OSA. The other example is alsoshown in FIG. 17, where the front wall of the base 20 is divided intothree fingers, 20 t to 20 v, two of which extend forward compared to therest finger. In the example shown in FIG. 17, both side fingers, 20 tand 20 u, protrude compared to the center finger 20 v. Moreover, anenvelop curve of the tip shape of these fingers traces the diameter D ofthe necked portions, 15 e or 16 e, of the OSA as shown in FIG. 17B,which enables to hold the OSA stably. In one modification, the envelopecurve of the tip shape may be slightly larger than the diameter D of thenecked portion, 15 e or 16 e, by taking a tolerance a of the diameter D.

To hold the OSA with three fingers whose positions along thelongitudinal direction are different from each other gives an equivalentmechanism that the OSA is held by a finger whose thickness is the samewith the gap between fingers. Thus, this type of the front fingers maygive a steady pressure to the OSA.

In the example shown in FIG. 17, the center finger 20 v positions behindthe side fingers, 20 t and 20 u. However, a positional relation betweenfingers is not restricted to those shown in FIGS. 17A and 17B. The sidefingers, 20 t and 20 u, may position behind the center finger 20 v. Afunction appeared in FIG. 17 may be accomplished by arrangements whereone of fingers positions behind the others. Two fingers whose positionsare different from each other may be also applicable.

In summary, one embodiment of the present invention provides a pluralityof fingers in the front end of the base 20. Some of fingers are bent ata first position, while the rest of fingers are bent at a secondposition different from the first position along the longitudinaldirection of the base 20. These fingers in the tip end thereof trace theouter shape of the necked portion of the OSA and hold the OSA reliably.These fingers correspond to a holding portion of the base 20.

When the sleeve, 15 d or 16 d, or the components for the opticalalignment are made of metal, the YAG laser welding may be a preferablemeans to fix the components permanently. However, the YAG laser weldingis unable for the resin made component or sleeve. An adhesive is onlytechnique to fix such resin made components. The present arrangement ofthe holding portion of the base 20 may show the preferable function topress the necked portion, 15 e or 16 e, of the OSA even if the neckedportion or the sleeve, 15 d or 16 d, is made of resin and fixed by theadhesive.

FIG. 18 shows a variation of the arrangement shown in FIG. 17. Thisvariation provides a shield block 30 made of electrically conductingmaterial and put between the fingers, 20 t to 20 v. The arrangement thatis shown in FIG. 18 without the shield block 30 causes a gap between thefingers. Moreover, depending on the envelope curve and its traceabilityfor the outer shape of the necked portion, 15 e or 16 e, another gap maybe occasionally formed between the base 20 and the OSA. Such gaps maydegrade the EMI tolerance.

In the variation shown in FIG. 18, the shield block 30 is set betweenthe fingers, 20 t to 20 v. Moreover, a surface of the shield block 30that faces and comes in contact to the necked portion, 15 e or 16 e,also has a shape to trace the outer shape of the necked portion. Thus,this arrangement enhances not only the holding capability of the base 20for the OSA but also the EMI shielding of the transceiver 1.

The shield block 30 has a simple outer shape, which does not restrict amaterial to be applied. An electrically conductive resin sheet, aradiation absorber, and a metal formed by, for instance, the extruding,the sheeting, the casting or the forging are usable.

The rear portion of the side 20 c forms the coupling portion 20 h byextending upward. The second portion 20 b includes a coupling surface 20i by bending this coupling portion 20 h inward. The coupling surface 20i includes a pair of tabs 20 j by bending a portion thereof downward, tobe put between the legs 21 k of the heat-conducting plate 21. The rearend of the coupling surface 20 i is partially bent downward to form thesurface 20 r and to protrude the rest portion 20 s rearward. Asdescribed later, the gap d₁ between the coupling surface 20 i is setslightly narrower than the width of the spacer tab 211. Assembling theheat conducting plate 21 with the base 20, the coupling surface 20 i ofthe base 20 is to be spread outward by the spacer tab 211, while thelegs 21 k of the heat conducting plate 21 presses the tabs 20 j inward,which fits the heat conducting plate 21 to the base 20. The front andrear ends of the coupling surface 20 i is bent downward to formsurfaces, 20 p and 20 r, to abut against the heat-conducting plate 21,which perform the similar function to that between the tab 20 j and theleg 21 k. The second portion 21 b of the heat conducting plate 21assembles with the base 20 by fitting the surfaces, 20 p and 20 r, inthe base 20 between the surfaces, 21 i and 21 s, and by fitting the tabs20 j between the legs 21 k.

Thus, the base 20 of the present invention is made from a metal platewith cutting, bending, and tapping without welding, gluing, screwing orcasting. The rib 20 q in the bottom secures the mechanical strength ofthe base 20. Moreover, the assembly with the substrate 17, thereceptacle member 13 and the heat conducting plate 21 may be carried outonly by fitting, which not only reduces the material cost but alsosimplifies the assembling process.

Next, the heat-dissipating mechanism of the transceiver 1 will bedescribed. It is inevitable to consume greater power by the devices usedin the transceiver 1 as the operational speed thereof increases.Therefore, the heat-dissipating mechanism for these devices becomesnecessary. However, since the pluggable transceiver 1 is used byinserting into/extracting from the cage 2, it is impossible to provide amechanism such as the heat-dissipating fin, although quite popular inthe electronic equipment, in the outer surface of the transceiver. Thesefins prevent the transceiver 1 from smoothly inserting into/extractingfrom the cage 2. Due to the same reason, it is prohibited that theoutside of the transceiver 1 comes in contact to the inside of the cage2.

The heat conducting plate 21 primarily performs the heat-dissipatingmechanism of the present transceiver 1. From FIG. 7A to FIG. 8Billustrate the heat-conducting plate 21 to be assembled with the base17, while FIGS. 9A and 9B illustrate the configuration of theheat-conducting plate 21 from the top (FIG. 9A) and from the bottom(FIG. 9B). The heat-conducting plate 21 is also made from a metal plateonly by cutting and bending. The plate 21 includes first to fourthportions, 21 a to 21 d. The first portion 21 a configures asubstantially rectangle surface 21 g, connected to the third portion 21c by bending a rear end thereof upward. This third portion 21 c connectsthe second portion 21 b by bending the other edge. The second portion 21b becomes substantially in parallel to the first portion 21 a and coversa portion of the first portion 21 a. The fourth portion 21 d is bent bythe other end of the second portion 21 b downward to form a surface 21i.

The first portion 21 a includes a surface 21 g with a substantiallyrectangular, back surfaces, 21 e and 21 f. A plurality of legs 21 jextends from a pair of sides thereof downward by bending, tips of whichcome in contact to the primary substrate 17 to press down the substrate17. A pair of support posts 21 m extends upward from the same sides,from which the legs 21 j extends downward. The tips of the support arebent to form the abutting surface 21 n. The back surface 21 e of thefirst portion 21 a comes in contact to the whole upper surface of the IC17 c installed on the substrate 17 to conduct heat from the IC 17 c tothe heat-conducting plate 21. The heat conducted to the plate 21 istransferred in the first portion 21 a rearward through other surface 21f of the first portion 21 a to the third portion 21 c. It is preferableto put the thermal sheet 24 between the IC 17 c and the back surface 21e of the plate 21 to enhance the efficiency of the heat conduction. Thelength of the leg 21 j is determined to take the thickness of thisthermal sheet 24 and that of the IC 17 c into consideration. It ispreferable to set the length of the leg 21 j slightly smaller than thetotal thickness of the IC 17 c and the sheet 24. To press this abuttingsurface 21 n downward by setting the cover 23 ensures the thermalcontact between the plate 21 and the sheet 24 and between the sheet 24and the IC 17 c.

The third portion 21 c extrudes rearward to come the end surface 21 h incontact to the inner end of the cage 2, which enhances the heattransferred to the plate 21 from the IC 17 c to dissipate to the cage 2.Even the end surface 21 h comes in contact to the cage 2, the insertioninto/extraction from the cage 2 of the transceiver 1 is not affected atall. Only the rear end surface 21 h of the transceiver 1 provides theeffective heat-dissipation path to the cage 2. The present transceiver 1enables to dissipate heat generated from the IC 17 c installed in themiddle thereof to the cage 2 by the heat conducting plate 21. Theperformance of the heat conduction of the plate 21 depends on the crosssection thereof. Since the width of the plate 21 is inherentlyrestricted by the width of the transceiver 1, the performance of theheat dissipation primarily depends on the thickness of the plate 21. Thepresent transceiver 1 uses copper based alloy with a thickness of 0.5mm, which shows a quite effective heat-dissipating function.

The second portion 21 b overlaps a rear half of the surface 21 of thefirst portion 21 a. The second portion 21 b also configures asubstantially rectangular, an upper surface 21 r thereof coming incontact with the inside of the cover 23 to assist the heat-dissipationfrom the plate 21 to the cover 23. Both sides of the second portion 21 bhave tabs 21 k by bending downward to put the tab 20 j formed incoupling surface 20 i of the base 20 therebetween. Moreover, the rear ofthe second portion 21 b is bent downward to form the spacer tab 211. Thewidth of this spacer tab 211 is set to be slightly wider than the gap d₁between the coupling surfaces 20 i of the base 20. Assembling the heatconducting plate 21 with the base 20, the spacer tab 211 and the tab 21k transversely put the coupling surface 20 i therebetween, while thesurfaces, 21 i and 21 s, longitudinally put the coupling surface 20 itherebetween. Thus, the heat-conducting plate 21 is assembled with thebase 20 only by fitting the coupling surface 20 i of the base 20 intothe second portion 21 b of the plate 21 without any screw, welding, orgluing, which enables to simplify the assembling process of thetransceiver 1.

The area of the first portion 21 a not overlaid by the second portion 21b mounts the supplementary substrate 18 as described later. One side ofthe first portion 21 a is cut to pass the FPC board connecting thesupplementary substrate 18 to the primary substrate 17.

FIGS. 10A and 10B illustrate one modification of the base 20 and theheat conducting plate 21 shown in FIG. 5 and FIG. 9, respectively. Thebase 200 illustrated in FIG. 10A is configured in the coupling surface200 i to be wider than the surface 20 i in the base 20 of FIG. 5A. Theside cross section of the heat conducting plate 210 has a zigzag shapenot the U-shaped configuration of the heat conducting plate 21. That is,the heat conducting plate 210 of this embodiment includes the firstportion 210 a coming in contact to the IC 17 c, the fourth portion 210 dbent upward at the rear end of the first portion 210 a, the secondportion 210 b bent at the upper end of the fourth portion 210 d, and thethird portion bent downward at the rear end of the second portion 210 b.The heat generated in the IC 17 c is conducted to the first portion 210a via the thermal sheet 24, transferred in the heat conducting plate210, and finally dissipated to the cage 2 at the rear end surface 210 hof the third portion 210 c.

Moreover, the third and fourth portions, 210 c and 210 d, configure toextend downward from the second portion 210 b so as to put the couplingsurface 200 i therebetween. The whole coupling surface 200 i of the base200 comes in contact to the back surface of the second portion 210 b.The first portion 210 a forms legs 210 j extending downward whilesupports 210 m extending upward from the sides thereof. The tip of thesupport 210 m becomes the abutting surface 210 n to come in contact tothe inside of the cover 23. The difference between two embodiments isthat the present heat conducting plate 210 presupposes not to installthe supplementary substrate 18. Although the first portion 210 a has aspace opened upward similar to the previous embodiment, this is for thedirect contact of the heat conducting plate 210 to the IC 17 c not toinstall the supplementary substrate 18.

Standards similar to those appeared in the previous embodiment may beapplied for the selection of the material and its thickness for the heatconducting plate 210 of this embodiment. Further, the heat conductingplate 210 is also made from a metal plate only by cutting and bendingwithout any welding and gluing. The plate 210 of this embodiment doesnot provide an overlaid portion, corresponding to the portion 21 f inthe previous embodiment, of the first portion 210 a and the secondportion 210 b. Accordingly, the plate 210 may save the metal plate. Theheat dissipating mechanism of this embodiment has the same efficiencywith those in the previous embodiment.

FIGS. 11A and 11B illustrate that, after installing the supplementarysubstrate 18 onto the first portion 21 a of the heat conducting plate21, the supporting plate 22 is set to hold the supplementary substrate18. As shown in FIG. 5B, the FPC board 18 d connects the supplementarysubstrate 18 to the edge of the primary substrate 17. Installing theprimary substrate 17 on the first portion 20 a of the base 20, andsetting the heat conducting plate 21 on the primary substrate 17, thesupplementary substrate 18 is set on the first portion 21 a of the heatconducting plate 21 so as to fold the FPC board 18 d. At that time, thesupport post 21 m of the heat conducting plate 21 passes through theopening 18 e in the supplementary substrate 18. The rear end 18 a of thesupplementary substrate is configured to protrude from the primaryportion thereof, as shown in FIG. 5B, which fits into the cuttingportion 21 q of the heat conducting plate 21. Since the supplementarysubstrate 18 is not fixed to the plate 21, the supporting plate 22assists to fix the supplementary substrate 18 to the plate 21. Moreover,the side of the FPC board 18 d forms a projection 18 g. This projectionis inserted behind the coupling portion 20 h at the assembling of thesupplementary substrate 18 onto the heat conducting plate 21.Accordingly, this projection may prevent the cover 23 from scratchingthe edge of the FPC board 18 d when setting the cover 23 to the bodyunit.

The supporting plate 22, as shown in FIG. 1C, is also made from a metalplate by cutting, bending, and tapping, and includes first to fourthportions, 22 a to 22 d. The first portion 22 a forms an opening 22 f anda step. The opening 22 f softens the resilient force of the tip portion22 j that comes in contact to the back surface 21 r of the heatconducting plate 21. The legs 221 in the first portion 22 a form a step22 g by cutting a portion of the tip thereof, which inserts into thenotch portion 18 f of the supplementary board 18. Moreover, the tabs 22i of the second portion 22 b comes in contact to the side of the supportpost 21 m of the heat conducting plate 21, and the legs 22 e in thefourth portion 22 d also forms a step 22 m by cutting a portion of thetip thereof, which inserts into the cutting portion 18 g formed in bothfront sides of the supplementary substrate 18. That is, the supportingplate 22 is assembled with the supplementary substrate 18 and the heatconducting plate 21 by three points, the steps, 22 g and 22 m, in thelegs of the supporting plate and the tab 22 i.

The third potion 22 c that connects the second portion 22 b to thefourth portion 22 d configures in a beam to be bent outward by about 0.2mm, which shows a resilient force. Putting the cover 23, the cover 23 inthe center thereof comes in contact to and presses down this beam.Consequently, the fourth portion 22 d of the supporting plate 22 ispressed downward to fix, by the tip 22 m thereof, the supplementarysubstrate 18 to the heat conducting plate 21.

FIG. 12A illustrates the transceiver 1 including the OSA unit 6, thebase 20, the primary and supplementary substrates, 17 and 18, the heatconducting plate 21 and the supporting plate 22, and completes theassembling thereof. The transceiver 1 shown in FIG. 12A further includesthe actuator 12 in the front end thereof. Next, the actuator 12 and theconfiguration of the front side of the receptacle member 13 where theactuator 12 is assembled will be described as referring to FIGS. 12B to12D.

FIG. 12B illustrates the actuator 12 from the bottom, while FIG. 12Cshows the configuration of the upper surface of the actuator 12. Theactuator 12 includes first to third portions, 12 a to 12 c, and iscapable of rotating around the axis 12 g formed in the third portion 12c, which makes a seesaw motion for the first and second portions, 12 aand 12 b, provided in both sides of the third portion 12 c. The frontend of the first portion 12 a forms a pressing surface 12 d, while bothsides thereof configures inner and outer sliding surfaces, 12 i and 12h, respectively. Rotating the bail 11, this rotational motion of thebail 11 may be converted to the up-and-down motion of the first portion12 a because two surfaces, 11 f and 11 h, of the bail 11 put these innerand outer sliding surfaces, 12 h and 12 i. That is, two surfaces, 11 fand 11 h, of the bail function as a cam. The second portion 12 bprovides an arm 12 f and a projection 12 e in the tip of this arm 12 f.The projection 12 e fixes the transceiver 1 to the cage 2 by engagingwith the opening of the cage 2 and, by the seesaw motion of the actuator12 due to the rotation of the bail 11, is brought inward to thetransceiver 1, which enables to disengage the projection 12 e with theopening and to release the transceiver 1 from the cage 2.

FIG. 12D illustrates the front configuration of the receptacle member13. Two openings, the optical receptacles, 10 a and 1 b, receives theoptical connector, and the TOSA 15 and the ROSA 16 installed on theother side of the receptacle member 13 may optically couple with theoptical fiber attached to the optical connector. On the bottom of thereceptacle member 13, in the center thereof, is configured with aprojection 13 e, whose section is semicircular, and, in both sidesthereof, are configured with beaked hooks. On the other hand, theactuator 12 forms a hollow 12 j in the center of the upper surfacethereof to receive the center projection 13 e of the receptacle member13, and the axis 12 g is fitted into the beaked hook 13 f. The centerprojection 13 e restricts the movement of the actuator 12 in thelongitudinal direction, while the beaked hook 13 f restricts theup-and-down motion thereof, accordingly, the actuator 12 may not bedisassembled with the receptacle member 13. On the side walls of thereceptacle member 13 are configured with the projection 13 d, whichbecomes the axis for the rotation of the bail 11, as a portion 13 pthereof is scooped.

FIG. 13A illustrates the bail 11 and the actuator 12, both assembledwith the receptacle member 13, viewed from the front side, while FIG.13B is a side view of these members. The bail 11 is a U-shaped memberincluding a pair of legs 11 b and a bridge 11 a connecting these legs 11b. Although the following description primarily concentrates on the bail11 made of metal by cutting and bending, the bail 11 may be made ofresin. A center of the leg 11 b forms an opening 11 c to receive theprojection 13 d on the side wall of the receptacle member 13, a portion11 d of the edge thereof extrudes into the opening 11 c and is setwithin the lacked portion 13 p of the projection 13 to restrict therotation of the bail 11.

Setting the bail in the neutral position, the initial position, theopenings, 10 a and 10 b, of the optical receptacle wholly exposes not tobe hidden by the bail 11. As shown in FIG. 13A, the sliding surface 11 hand the cam surface 11 f of the bail 11 put and come into contact to theinner and outer sliding surfaces, 12 h and 12 i. Rotating the bail 11,this rotational motion of the bail 11 operates to the actuator 12. Thatis, until the angle of the rotation θ, the bail 11 makes no operation tothe actuator 12. The angle θ is determined when the cam surface 11 fwholly comes in contact to the inner sliding surface 12 i, as shown inFIG. 13B.

Further rotating the bail 11, the cam surface 11 f presses down theinner sliding surface 12 i, which continues until the outer surface 11 iof the leg 11 b comes in contact to the inner sliding surface 12 i.Thus, by the first portion 12 a of the actuator 12 pressing downward,the projection 12 e in the second portion 12 b is drawn up by the seesawmotion of the actuator 12, which may disengage the projection 12 e withthe opening of the cage 2.

During the rotation of the bail 11, the sliding surface 11 h of the bail11 supports the outer sliding surface 12 h of the actuator 12,consequently, the actuator 12 is inevitably connected with the bail 11.In other words, the actuator 12 makes the seesaw motion as the inner andouter sliding surfaces, 12 h and 12 i, are put between the cam surface11 f and the sliding surface 11 h of the bail 11. Moreover, the cover 23supports the actuator 12 by the fin 23 d thereof extending from thefront edge of the cover 23 (FIG. 14A). The projection 11 d within theopening 11 c of the leg 11 b slides only in the lacked portion 13 p ofthe projection 13 d. This combination of the projection 11 d and thelacked portion 13 p operates as the stopper for the rotation of the bail11. When the bail 11 returns from the rotated position to the neutralposition, the initial position in FIG. 13A, the operation mentionedabove are performed in the opposite procedure.

In the description above, the bail 11 is rotated to disengage thetransceiver 1 with the cage 2 by pulling the projection 12 e inward.However, when the host system densely installs a plurality of cages 2and the transceivers neighbor to the target transceiver receive theoptical connector attached with the optical cable, a situation may occurthat the bail can not rotate because the optical cables of the neighbortransceivers prevent from touching the bridge portion 11 a of the bail11. The transceiver of the present invention may exhibit the samefunction with the rotation of the bail 11 by pressing down the front end12 d of the actuator 12.

As shown in FIG. 13 b, pressing the front end 12 d of the actuator 12downward, the outer sliding surface 12 h pushes the sliding surface 11 hof the bail 11 rearward, which influences the rotational moment on thebail 11. The combination of the conventional bail and the actuator maynot convert the force downward for the actuator 12 into the rotationalmoment of the bail 11. The force applied to the actuator 12 may notconvert to the rotational moment of the bail 11 because the bail itselfoperates as the stopper, thereby being unable to release the transceiver1 from the cage 2. The mechanism provided in the present inventionconverts the force applied to the front end of the actuator 12 isadequately converted to the rotational motion of the bail 11, whichenables the transceiver 1 to be released from the cage 2.

Recently, the pluggable transceiver 1 is proposed to be applied in thewavelength division multiplexed (WDM) system. In the WDM system usingthe pluggable transceiver, which provides functions of the opticaltransmission and the optical reception, the emission wavelength of theoptical transmission function is set to be a preset value, and aplurality of optical signals each having the preset wavelength istransmitted by being multiplexed in the outside of the transceiver. Inthis case, each transceiver is inevitable to have an inherent emissionwavelength. However, as shown in FIGS. 1 and 2, even the label attachedin the upper or the side of the body records the information of theemission wavelength, it is unable to discriminate the information whenthe transceiver 1 is set within the cage 2. Accordingly, the presenttransceiver proposes a configuration that the bridge portion 11 a of thebail 11 provides the colored identification, which enables todistinguish visually the emission wavelength even when the transceiver 1is in the cage 2.

According to the WDM communication standard in the wavelength band of1.5 μm, the optical signals are divided into 64 channels by the intervalof 0.8 nm, which corresponds to 100 GHz in the frequency, and aremultiplexed in the wavelength band from 1530 nm to 1650 nm. In order todistinguish respective wavelengths, the last two digits in the integerpart and one digit after the decimal point, total three digits, may bemarked in the color code. One example of color codes is shown in thefollowing table: TABLE Example of color code Number Color 0 Black 1Brown 2 Red 3 Orange 4 Yellow 5 Green 6 Blue 7 Magenta 8 Gray 9 While

By spacing between the first two digits, which corresponds to theinteger part, and the last one digit that corresponds to the one afterthe decimal points, the position of the decimal point maybedistinguished. Such colored codes can be recognized when the bail 11 isrotated in front of the optical receptacles, 10 a and 10 b, even whenthe transceiver 1 is in the cage 2. In stead of spacing between thedigits, to mark the identification may be recognizable to denote theposition of the decimal point and to distinguish the emissionwavelength. Moreover, three digits for the integer part, the total offour digits, may be applicable for the identification.

The cover 23 is made from a metal plate with a thickness of about 0.3 mmby cutting and bending without any welding and gluing. The metal usedfor the cover 23 may be stainless, iron or copper alloy. The cover 23 isfit from the rear side of the transceiver 1 to cover the body unitthereof exposing only the optical receptacle 10. The bottom of the cover23 forms a slit with two edges, 23 a and 23 b, forming this slit arefitted within the rib 20 q formed in the bottom 20 g of the base 20, asshown in FIG. 14B. This configuration of the slit and the rib 20 qstrengthens the transceiver 1 against the stress despite the cover 23 ismade from a metal plate by bending.

The cover 23 forms a large opening 23 e in the front bottom to protrudethe projection 12 e of the actuator 12 to engage with the opening in thecage 2. The upper surface of the cover 23 forms a plurality ofstructures, as shown in FIG. 1A, which includes two slits parallel toeach other and a portion between these two slits is bent inward. Thisbent portion has a resilient function and comes in contact to the secondportion 21 b and to the abutting surface 21 n of the heat conductingplate 21 when the cover 23 is fit to the body unit. Consequently, theheat conducting plate 21 not only securely comes in contact to the IC 17c but also ensures the heat dissipation path from the heat conductingplate 21 to the cover 23.

FIGS. 15A and 15B illustrate the front end of the transceiver 1 fittedwith the cover 23. Fins, 14 d and 14 f, protrude from the front end ofthe cover 23. The upper of the transceiver 1 also forms the ground tab23 g that surrounds the fin 14 f. In the midsection 14 m of the fin 14 fprotrudes to securely come in contact to the inside of the cage 2. Itmay be applicable that this midsection 14 m projects outward by formingtwo slits parallel to each other and surrounding the mid section 14 m.That is, the fin 14 f may be the double fin with the sub-fin 14 m in thetip thereof. The double fin may have another slit connecting those twoslits in the ends thereof. Moreover, another fin 14 d may form themidsection protruding from the peripheral thereof, and the double finstructure 14 m may be also applicable to this another fin 14 d.

By applying such configuration to the fins, 14 f and 14 d, thetransceiver 1 may securely come in contact to the cage 2. The multiplecontacts of the fins, 14 f and 14 d, the double fin structure 14 m, andthe ground tab 23 g of the cover 23 makes the contact of the transceiver1 to the cage 2 secure. Since the cage 2 is made from a metal plate, theshape thereof is easily deformed. Even when the transceiver 1 is formedin firm, the secure contact between the transceiver 1 and the cage 2 maybe performed if the cage 2 is deformed. The multiple contact of thepresent invention ensures the secure contact therebetween.

FIG. 15B illustrates the bottom of the front end of the transceiver 1.The fin 23 d of the cover supports the actuator 12 and the projection 12e protrudes from the opening 23 e. Moreover, the fin 14 c protrudes fromboth sides of the fin 23 d to set in the tip thereof within the grooveat the boundary between the second and third portions, 13 b and 13 c,respectively, of the receptacle member 13. The side fin 14 d of the tabplate 14 is also set within the groove at the boundary between secondand third portions, 13 b and 13 c.

Next, an assembling process of the present optical transceiver will bedescribed in sequence.

1. Assembling of the Receptacle Member with the Tab Plate

First, as shown in FIG. 3A, the tab plate 14 is attached to thereceptacle member 13. As described previously, the second portion 14 bof the tab plate 14 is folded twice to configure a U-shape crosssection. The opening of this U-shaped second portion 14 b receives thethird portion 13 c of the receptacle member 13. At that time, the latch14 k, which comes in contact to the TOSA 15 and the ROSA 16, is set inthe groove 13 n provided in the bottom of the U-shaped cutting. The tabplate 14 is assembled with the receptacle member 13 by engaging thelatch tab 14 e with the projection 13 g in the side of the receptaclemember 13.

2. Installing the OSAs in the Receptacle Member

Next, as shown in FIG. 4A, the TOSA 15 and the ROSA 16 are installed inthe receptacle member 13. Respective OSAs, 15 and 16, provide a pair offlanges, 15 c and 16 c, in the head portion thereof, 15 d and 16 d,which is the so-called sleeve. These flanges, 15 c and 16 c, sandwichthe wall 13 q therebetween that forms the U-shaped cutting. At thattime, the tab plate 14 is sandwiched between the wall 13 q and one ofthe flanges in respective OSAs, 15 and 16. The width of the U-shapedcutting in the tab plate 14 is configured to be slightly smaller thanthe diameter of the sleeves, 15 d and 16 d. Accordingly, although theOSAs are easily set within the cutting by deforming the tab plate 14,the OSAs once set are hard to be disassembled. On the other hand, thewidth of the U-shaped cutting of the receptacle member 13 is slightlywider than the diameter of the sleeve, accordingly, to set the OSAs, 15and 16, within the receptacle member 13 may be carried out without anyproblem. The tab plate 14 may configure an identification mark in theside where the TOSA is to be installed to distinguish the TOSA 15 fromthe ROSA 16. The assembly of the OSA unit 6 has completed afterinstalling the OSAs, 15 and 16, in the receptacle member 13 with the tabplate 14. The OSA unit 6 is illustrated in FIG. 4B.

3. Installing the Substrate in the Base

Next, the primary substrate 17, on which the electronic circuit ismounted in advance, is to be assembled with the base 20. Prior to theassembling of the substrate 17, the thermal sheet 27 is put on theportion where the TOSA is to be mounted and the insulating film 19 isattached to the supplementary substrate 18 in the surface opposite tothe surface the electronic component is mounted (FIG. 5B).

The primary substrate 17 is temporarily fixed with the OSA unit 6. Thistemporal fixing is carried out by putting the substrate 17 between thelead pins, 15 b and 16 b, when the OSAs, 15 and 16, provide the leadpins, without soldering. While, when the OSAs, 15 and 16, are connectedto the substrate 17 with the FPC board, the soldering between the FPCboard and the substrate, and between the FPC board and the OSAs, 15 and16, may be carried out. Occasionally, the OSAs, 15 and 16, soldered withthe FPC board may be connected or soldered with the substrate 17 afterassembling the OSA unit 6 with the base. Some fixture to assist theassembly of the OSA unit 6 with the base 20 may be utilized in thisprocess.

Sliding the rear part of the substrate 17 under the coupling surface 20i of the base 20, the step 17 d formed in the side of the substrate 17abuts against the side of the coupling portion 20 h, which automaticallypositions the substrate 17 on the base 20 in the longitudinal directionof the transceiver 1. Pressing down the substrate 17 as abutting againstthe coupling portion 20 h, the projection 20 k in the side 20 c of thebase 20 fits in the notch 17 e formed in the side of the substrate 17.By configuring the width of the projection 20 k slightly wider than thatof the notch 17 e, the relative position of the substrate 17 to the base20 may be automatically and precisely determined. In such configuration,once fitting the substrate 17 in the base 20, the substrate 17 is hardto disassemble. A portion of the side 20 c of the base 20 is bent inwardto stabilize the position of the substrate 17 put thereon.

Subsequently, the OSA unit 6 is set to the base 20, as shown in FIGS. 6Aand 6B. Pressing the base 20 downward, as the OSA unit 6 is temporarilyfixed with the substrate 17, the projection 13 m provided in the side ofthe OSA unit 6, practically provided in the side of the receptaclemember 13, engages with the opening 20 a of the support 20 d. In themeantime of this engagement between the projection 13 m and the opening20 e, the center post 20 f formed in the front end of the base 20inserts into the opening 13 r in the center of the receptacle member 13.Thus, the OSA unit 6 is fixed to the base 20 by three positions, i.e.,two positions in the side and one position in the front end thereof.Moreover, these three fixings are complementary to each other becausethe fixing in the side is between the convex in the OSA unit 6 and theconcavity in the base 20, on the other hand, the fixing in the front endis between the concavity in the OSA unit 6 and the convex in the base 6.The bracket 25 is fit to the ROSA 16 after assembling the OSA unit 6 andthe primary substrate 17 with the base 20.

4. Installing the Heat Conducting Plate

Next, the heat conducting plate 21 is installed on the base 20, which isillustrated in successive from FIG. 7A to FIG. 8B. First, the thermalsheet 24 is attached to the IC 17 c in direct thereto or via some resinmaterial with flexibility and good thermal conductivity to enhance theheat conductance to the heat conducting plate 21. Subsequently,inserting the rear end portion 20 s of the base 20 into the openingbetween the surface 21 h and the spacer tab 211, of the heat conductingplate 21 and rotating the heat conducting plate 21 as touching the innersurface 21 s of the third portion 21 to the surface 20 r of the base 20,the surface 21 i fits to the front end 20 p of the coupling surface 20i. Moreover, the spacer tab 211 widens the gap between the couplingsurface 20 i while the legs 21 k put the tabs 20 j of the base 20therebetween. That is, four sides, 21 s, 21 i and 21 k, surrounding thesecond portion 21 b of the plate 21 wrap and fit to the coupling surface20 i of the base 20. The first portion 21 a of the plate 21 in the backsurface 21 e thereof comes in direct contact to the thermal sheet 24 onthe IC 17 c. The front legs 21 j of the plate 21 presses down theprimary substrate 17 by fixing the plate 17 to the base 20.

Thus, the assembly of the heat conducting plate 21 with the base 20 maybe carried out without any screws only by mechanically fitting of twomembers using the resiliency inherently attributed to metal materials.Therefore, the present transceiver has the configuration quite superiorproductivity.

The heat generated in the IC 17 c is conducted by the heat conductingplate 21 to the rear end of the transceiver 1, and finally dissipated tothe cage 2 at the rear end surface 21 h. A substantial gap between thetransceiver 1 and the cage is necessary to ensure the smooth insertioninto/extraction from the cage 2. Therefore, even the heat generatedwithin the transceiver 1 is effectively conducted to the cover 23; it iseffective to radiate thus conducted heat to the cage 2. However, onlythe rear end of the transceiver 1 may touch to the cage 2 when thetransceiver 1 is adequately set within the cage 2 and the plug of thetransceiver 1 mates with the connector in the inner end of the cage 2.Accordingly, to conduct heat generated within the transceiver 1 to therear end thereof may enhance the efficiency of the heat dissipation. Theheat conducting plate adopted in the present transceiver 1 may provide asolution for the subject above mentioned.

5. Soldering the Lead Pins of the OSAs

Next, the lead pins, 15 b and 16 b, extending from the OSAs, 15 and 16,are soldered with the primary substrate 17. The processes thus describeddetermine the relative position of the primary substrate 17 and the OSAunit 6 through the base 20, accordingly, the soldering, which is a typeof the permanent fixing, between the lead pins, 15 b and 16 b, and theelectrodes, 17 a and 17 b, on the substrate 17 may be carried out. TheOSAs, 15 and 16, are necessary to position relatively to the receptaclemember 13 to provide the optical receptacle 10 following the standard.On the other hand, the primary substrate 17 is necessary to positionrelatively to the covet 23 to ensure the smooth insertion into theelectrical connector provided in the inner end of the cage 2. Thus, toconnect the substrate 17 with the lead pins, 15 b and 16 b, in permanentafter the positions of the substrate 17 and the OSAs, 15 and 16, mayprevent the mechanical distortion from localizing in the solderingpoint.

When the bracket 25 is attached to the ROSA 16, the soldering betweenthis bracket 25 and the ROSA 16 is also carried out simultaneously tothe soldering of the lead pins, 15 b and 16 b. When the FPC board isused for connecting to the substrate 17, the soldering thereof may beoptionally carried out after the assembly of the OSA unit 6. Theflexibility inherently attributed to the FPC board can compensate thepositional discrepancy between the substrate 17 and the OSA unit 6. Thesoldering for the electrodes, 17 a and 17 b formed on the primarysurface of the substrate 17 may be carried out in the portion exposedbetween the heat conducting plate 17 and the tab plate 14, while throughthe opening 201 formed in the bottom 20 g of the base 20 for theelectrodes in the back side of the substrate 17.

6. Installing the Supplementary Substrate

The supplementary substrate 18 connects to the one side edge of theprimary substrate 17 with the FPC board 18 d, namely, the FPC board 18 dpasses through the cutting portion 21 p of the heat conducting plate 21to connect to the primary substrate 17. The supplementary substrate 18is installed on the heat conducting plate 21 in the first portion 21 athereof by folding the FPC board 18 d as the support post 21 m passesthe opening 18 e in the supplementary substrate 18. Since the backsurface of the supplementary substrate 18 exposes the interconnections,the insulating film 19 is put thereon, as shown in FIG. 5B.

The supplementary substrate 18, which is installed on the first portion21 a, is fixed by the supporting plate 22, as shown in FIGS. 11A and11B. The tip 21 j of the first portion 21 a of the supporting plate 22is inserted under the second portion 21 b from the cutting 21 q as thefourth portion 22 d is lifted up. The first portion 22 a positionswithin the cutting 21 q, and the step 22 g in the leg 221 of the firstportion 22 a fit to the notch portion 18 f of the supplementarysubstrate 18. Pressing down the second to fourth portions, 22 b to 22 d,the tab 22 i in the second portion 22 b abuts against the side of thesupport post 21 m, and the step 22 m in the leg 22 e of the fourthportion 22 d fits to the cutting 18 g of the supplementary substrate 18.Therefore, the supporting plate 22 is assembled with the heat conductingplate 21 and the base 20 by the step 22 g, the tab 22 i and the step 22m. Setting the cover 23 to put the body unit of the transceiver 1therein, the beam portion 22 k bent upward by about 0.2 mm abuts againstthe inner surface of the cover 23 such that the cover 23 presses thisbeam portion 22 k down, consequently, the supplementary substrate 18 isfixed to the heat conducting plate 21.

7. Assembling the Actuator

Next, the actuator 12 is attached with the transceiver 1 as shown inFIGS. 12B to 12D. The actuator 12, which is made of resin, is assembledwith the receptacle member 13 with the axis 12 g thereof being fit tothe beaked hook 13 f and the hollow 12 j receiving the center projection13 e of the receptacle member 13. Sliding the actuator 12 on the bottomsurface of the receptacle member 13 from the front side, the centerprojection 13 e is set within the hollow 12 j as deforming the beakedhook 13 f and the projection 13 e itself. In the same time, the axis 12g is set within the beaked hook 13 f. Due to the tip shape of the beakedhook 13 f, the actuator 12 one set within the hook 13 f is hard todisassemble, namely, the actuator does not fall even the bottom of thetransceiver 1 directs downward.

8. Setting the Cover

Prior to the setting of the cover 23, the thermal sheet 26 is attached,if necessary, to the portion of the TOSA 15 and the ROSA 16 exposedbetween the receptacle member 13 and the supplementary substrate 18. Thethickness of this thermal sheet 26 is adjusted such that the top surfaceof the sheet 26 comes in directly contact to the ceiling of the cover 23when the cover 23 is set to the body unit. The thermal sheet 26 mayenhance the heat dissipating efficiency from the TOSA 15 and the ROSA tothe cover 23. The heat thus conducted to the cover 23 may not onlyradiate to the cage 2 but also conduct to the rear end of the cover 23and may be conducted to the inner end of the cage 2.

The cover 23 configures the latch tab 23 f with an opening in both frontsides thereof, as shown in FIG. 14A, while, forms the stopper 23 h inthe rear end. The opening provided in the latch tab 23 f is to beengaged with the projection 13 g provided in the side of the receptaclemember 13. The cover 23 is set to the body unit such that the stopper 23h abuts against the outer side portion 21 u of the rear end surface 21h. The fin 23 d in the front bottom of the cover 23 extends forward, andthe projection 12 e formed in the actuator 12 protrudes from the opening23 e in the root of this fin 23 d. The fin 23 d supports the actuator12.

As shown in FIG. 1, on the upper surface of the cover 23 is configuredwith the structure with two slits and the portion 23 c between theseslits being bent inward. This bent portion 23 c comes in contact to theupper surface 21 r and the abutting surface 21 in of the heat conductingplate 21 to press the plate 21 downward. Since this bent portion 23 chas an arched shape, it makes no problem for setting/removing the cover23 from the body unit.

9. Installing the Bail

The bail 11 is attached to the receptacle member 13. The projection 13 din the side wall of the receptacle member 13 inserts into the opening 11c formed in the leg portion 11 b of the bail 11, as shown in FIGS. 13Aand 13B. The attachment of the bail 11 can be easily carried out byspreading the leg portions 11 b in outward. Setting the actuator 12 inthe neutral position, the inner and outer sliding surfaces, 12 i and 12h, is put between the cam surface 11 f and the sliding surface 11 h inthe tip 11 g of the leg 11 b. The projection 12 e of the actuator 12 canbe simply pulled inward by rotating the bail 11 or by pressing the frontend 12 d of the actuator 12 downward, which may release the transceiver1 from the cage 2.

Finally, labels, 28 a to 28 c, are stuck on the top and side surfaces ofthe transceiver 1 to complete the assembly. The label 28 a on the topsurface may be covered by a transparent film 28 d to prevent thereoffrom peeling off by the insertion/extraction of the transceiver 1 to thecage 2.

The configuration and the assembling process of the present transceiverare thus described with referring to accompanying drawings. Since thepresent transceiver 1 assembles metal components made by cutting,bending or tapping the single metal plate and fits these metalcomponents without any screws or other joining means, the cost not onlythe components themselves but also the assembling process can bereduced. Moreover, since the present transceiver 1 provides the heatconducting plate to dissipate heat from the IC 17 c installed in thecenter of the transceiver 1 to the outside thereof, besides the heatconducting plate made of copper alloy, the heat dissipation efficiencycan be enhanced for the transceiver 1 to be apply to the high speedapplication over giga-hertz frequency band.

The optical transceiver according to the present invention provides, inaddition to the fingered structure of the front end of the base 20, ashield member 40 to enhance the EMI tolerance. By setting the shieldmember 40 in the second necked portion, 15 f or 16 f, of the OSA andelectrically makes a portion of the shield member 40 contact with thetab plate 14 and the base 20, a gap inevitably induced between the base20 and the OSA may be effectively covered to enhance the EMIcharacteristic of the transceiver 1. FIGS. 19A and 19B show the shieldmember 40 viewed from the front (FIG. 19A) and from the rear (FIG. 19B).This shield member 40 is also made of metal plate, such as stainlesssteel, only by cutting and bending.

The shield member 40 includes planes, 40 b and 40 c, by bending theoriginal plane 40 a at the upper side thereof. For the bottom side, theplane 40 a is folded twice so as to wrap the tip of the plane 40 c toform the plane 40 h and a plurality of fingers 40 d, three fingers inthis embodiment. Another finger 40 e protrudes from the plane 40 a to aside opposite to the plane 40 h. Two U-shaped cuts formed in the plane40 a correspond to the U-shaped cut formed in the receptacle member 13and the tab plate 14. The width W of thus U-shaped cut is narrower thanthe width of the U-shaped cut of the tab plate 14 and wider than thediameter of the second necked portion, 15 f or 16 f, of the OSA becausethis shield member 40 is set in the second necked portion, 15 f or 16 f,and the diameter of this second necked portion is smaller than that ofthe first necked portion, 15 e or 16 e, as shown in FIG. 16. Thus, toset this shield member in the second necked portions, 15 f and 16 f,does not define the relative position of the shield member 40 withrespect to the OSA or the receptacle member 13.

FIG. 20A shows a process to assemble this shield member 40 with the TOSA15 and the ROSA 16, they are already built with the receptacle member 13and the tab plate 14. FIG. 20B is plan view of the transceiver 1 afterassembling the shield member 40 with the OSA unit 6 before assemblingthe OSA unit 6 with the base 20. The shield member 40 is set as theplane 40 b thereof faces up, where a surface not appeared in FIG. 20Acorresponds to the top surface of the transceiver 1, and stuffed untilthe plane 40 b abuts against the bottom surface 14 i of the tab plate14. In such arrangement, the tip of the fingers 40 d does not come incontact to the necked portions, 15 e and 16 e, of the OSA. As explained,the fingers, 20 t to 20 v, of the base 20 abuts against and holds theOSA in the first necked portions, 15 e and 16 e. It is unfavorable thatthis finger 40 d of the shield member 40 abuts against the OSA becauseit causes an excess stress being applied to the OSA.

The horizontal position of the shield member 40 is determined by theedge 40 f in the plane 40 h thereof touching to the outer wall of theU-shaped cut of the receptacle member 13. That is, when the shieldmember 40 is inserted into the second necked portion, 15 f or 16 f, ofthe OSA, and abutted the top of the member 40 against the bottom surface14 i, to make the edge 40 f of the plane 40 h in contact to the edge ofthe U-shaped cut of the tab plate 14 defines the horizontal position ofthe shield member 40, and such arrangement does not make the tip of thefinger 40 d in contact to the OSA although the finger 40 d is set withinthe first necked portions, 15 e and 16 e. Thus, only the fingerpositioned in outermost has a function to position the shield member 40with respect to the OSA unit 6.

The base 20 is built with the OSA unit 6 after setting the shield member40 in the second necked portions, 15 f and 16 f, as described. Thecenter post 20 f of the base 20 mates with the socked 14 n of the tabplate 14 and the opening 20 e in the side 20 d of the base engages withthe projection 13 g in the side of the receptacle member 13. In thisarrangement, the fingers, 20 t to 20 v, in the front end of the base 20pushes the first necked portions, 15 e and 16 e, of the OSA to positionthe OSA with respect to the receptacle member 13. Moreover, theprotruding finger 40 e of the shield member 40 comes in contact with therib 20 q of the base and both edges 40 i comes in contact to respectivesides 20 d of the base 20, which secures the electrical contact betweenthe base 20 and the tab plate 14. FIG. 20B also shows positions, towhich the front fingers, 20 t to 20 v, of the base 20 is set, by hatchedareas.

Thus, by setting the shield member 40 according to the present inventionin the necked portion of the OSA and securing the electrical contactbetween the base 20 and the tab plate 14, the shield member 40 caneffectively cover a gap induced between the base 20 and the OSA, whenthe transceiver is viewed from the front of the transceiver, whichenhances the EMI characteristic.

1. An optical transceiver, comprising: an optical subassembly having apair of flanges and first and second necked portions, the first neckedportion being arranged between the pair of flanges; a receptacle memberhaving a U-shaped cut where the first necked portion of the opticalsubassembly is set therein; a tab plate made of metal and put betweenthe receptacle member and one of the pair of flanges of the opticalsubassembly; a substrate for installing an electronic circuit thatelectrically communicates with the optical subassembly; and a basehaving a primary surface for installing the substrate thereon, the baseproviding a finger in a front end portion thereof, wherein the fingersecures the first necked portion of the optical subassembly to set thefirst necked portion within the U-shaped cut of the receptacle member.2. The optical transceiver according to claim 1, wherein the finger isbent from the primary surface of the base, and wherein a tip shape ofthe bent portion of the finger traces an outer shape of the first neckedportion of the optical subassembly.
 3. The optical transceiver accordingto claim 1, wherein the finger is divided in a plurality of fingers eachbent from the primary surface of the base, and wherein at least one ofthe fingers extrudes more than the other of fingers to form a gapbetween at least one of the fingers and the other fingers.
 4. Theoptical transceiver according to claim 3, wherein an envelope curve of atip of the bent portion of the fingers traces an outer shape of thefirst necked portion of the optical subassembly.
 5. The opticaltransceiver according to claim 3, further including a shield block madeof electrically conducting material and set between at least one offingers and the other of fingers.
 6. The optical transceiver accordingto claim 1, further comprising a shield plate made of metal and setwithin the second necked portion of the optical subassembly.
 7. Theoptical transceiver according to claim 6, wherein the shield plate comesin electrically contact with the base and the tab plate to shield theoptical transceiver.
 8. The optical transceiver according to claim 1,wherein the tab plate and the base are made of metal plate only bycutting, bending and extruding, and wherein the tab plate provides asocket and the base provides a post in the front end thereof, the postbeing mated with the socked of the tab plate.
 9. The optical transceiveraccording to claim 8, wherein the base provides a side with an openingand the receptacle member provides a projection in a side thereofengaged with the opening of the side of the base.
 10. The opticaltransceiver according to claim 8, wherein the receptacle member is madeof resin coated with metal.